Im trying to setup dual booting. The laptop came with Windows 8 pre installed and UEFI and quick Boot enabled. In the Ubuntu UEFI documentation it tells us to create a EFI partition in the beginning of the disk. But if we do this, the Windows 8 won't boot right?

2 Answers
2

The EFI System Partition (ESP) is intended to be shared across OSes, so you should be able to use the one that already exists. It's also legal to create multiple ESPs on a single disk, but this can be confusing, so I recommend against it. AFAIK, Windows will boot with multiple ESPs, but Windows 7's installer becomes confused by such configurations. I don't know if the Windows 8 installer (or repair utilities) become confused in a similar way. If they do, creating a second ESP is inadvisable for this reason alone.

How can we tell Ubuntu to use that Windows's partition? Do we have to set a mount point for that partition on installation? Once It asked me to create a separate partition and after rebooting, it didn't load the GRUB... instead moved directly to Windows 8
–
EApubsDec 25 '12 at 3:27

When you use the default settings, the Ubuntu installer should use the existing ESP automatically. (Note that it's not a "Windows partition"; it's OS-independent.) If the Ubuntu installer is failing to use the existing ESP, then that's either a bug in the installer or it indicates some sort of problem in the partitioning or filesystem -- maybe the ESP is too small or is mis-labelled, for instance. If you partition manually, you may need to identify the ESP as such to the installer. IIRC, Ubuntu uses a slightly unusual name, like "EFI boot partition." You do this in the partition setup screen
–
Rod SmithDec 27 '12 at 3:11

During the Ubuntu installation, when setting the mount points for the partitions under the Something Else option; in the pull down for the mount point for the /Boot partition, select EFI from the available options.

On my W8 installation, Windows 8 certainly still boots with this configuration:

For your reference, this is how I achieved dual boot with vendor (HP) installed Windows 8 / Ubuntu 12.10 on the machine that’s in the linked data sheet, with manufacturing date 08/12:

• •Disable Secure Boot. I could not achieve boot in any configuration with it on.
• •UEFI boot scheme (not Legacy BIOS). I tried Legacy mode, and can boot from disk, but not from an installation on the hard drive. UEFI flies right by it during boot every way I tried with it on.

In Ubuntu:
• •/Boot=EFI, /=EXT4, /Home=EXT4, SWAP=swap.

With this configuration I can boot with user intervention during the boot sequence:
1) During the boot sequence, select F9 to obtain Boot options in UEFI (BIOS)
2) In UEFI / BIOS, select the available Ubuntu Linux 2.6.32-21 option and proceed.
3) Ubuntu GRUB boot option screen is now available. Select preferred option and proceed.
4) I'm in.